Clippy lints / Complexity
Clippy lint · Complexity · checked with Clippy 0.1.99
clippy::manual_div_ceil: Checks for an expression like (x + (y - 1)) / y which is a common manual reimplementation of x.div_ceil(y)
What it meansChecks for an expression like (x + (y - 1)) / y which is a common manual reimplementation of x.div_ceil(y). It is in the complexity group and warns by default.
Does it matter?
It’s simpler, clearer and more readable.
Code that does something simple in a complicated way. Warns by default.
How to fix it
Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.
Flagged
let x: i32 = 7;
let y: i32 = 4;
let div = (x + (y - 1)) / y;
Write this instead
#![feature(int_roundings)]
let x: i32 = 7;
let y: i32 = 4;
let div = x.div_ceil(y);
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::manual_div_ceil)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
manual_div_ceil = "allow"One run
cargo clippy -- -A clippy::manual-div-ceilThe [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.
Settings in clippy.toml
msrv: The minimum rust version that the project supports. Defaults to the rust-version field in Cargo.toml
Clippy's own documentation
What it does
Checks for an expression like (x + (y - 1)) / y which is a common manual reimplementation
of x.div_ceil(y).
Why is this bad?
It’s simpler, clearer and more readable.
Example
let x: i32 = 7;
let y: i32 = 4;
let div = (x + (y - 1)) / y;
Use instead:
#![feature(int_roundings)]
let x: i32 = 7;
let y: i32 = 4;
let div = x.div_ceil(y);
Configuration
-
msrv: The minimum rust version that the project supports. Defaults to therust-versionfield inCargo.toml(default:
current version)
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- too_many_argumentsChecks for functions with too many parameters
- clone_on_copyusing `clone` on type `u64` which implements the `Copy` trait
- type_complexityChecks for types used in structs, parameters and let declarations above a certain complexity threshold
- manual_c_str_literalsChecks for the manual creation of C strings (a string with a NUL byte at the end), either through one of the CStr constructor functions, or more plainly by calling .as_ptr() on a (byte) string literal with a hardcoded \0 byte at the end
- manual_checked_opsDetects manual zero checks before dividing integers, such as if x != 0 { y / x }
- manual_clampIdentifies good opportunities for a clamp function from std or core, and suggests using it
- manual_filtermanual implementation of `Option::filter`
- manual_filter_map`filter(..).map(..)` can be simplified as `filter_map(..)`
- manual_findmanual implementation of `Iterator::find`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::too_many_argumentsChecks for functions with too many parametersRead it next →Did this answer your question?